I successfully dual booted Ubuntu 20.04 on windows 7. After a month, I removed my windows 7 and since then I started experiencing black screen at boot (without blinking cursor) which I somehow overcome with pressing the shift key or esc key, etc. My laptop use a hybrid Intel/AMD graphic card which gave me problems on and off even while I was on windows.

Thinking a fresh install would solve the problem, I reinstalled Ubuntu (only) and encountered error: unknown filesystem. While trying to fix this, I might have messed somehow that I have the black screen everytime I try to boot, unable to even access the bios (and hence can't even live boot).

It would be great if someone could help me out on this. Thanks in anticipation!


I was able to finally get back to the

error: unknown filesystem

grub rescue >

after clearing the CMOS following a guide similar to the explanations given here https://www.lifewire.com/how-to-clear-cmos-2624545

Following this guide How to fix "error: unknown filesystem. grub rescue> I eventually boot into my linux mint/ubuntu finally.

Hope someone with a similar problem finds it helpful!

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